1. intro to comp & c++ programming

1

Chapter 1 – Introduction to Computers
and C++ Programming
Outline
1.1
Introduction
1.2
What is a Computer?
1.3
Computer Organization
1.4
Evolution of Operating Systems
1.5
Personal Computing, Distributed Computing and
Client/Server Computing
1.6
Machine Languages, Assembly Languages, and High-Level
Languages
1.7
History of C and C++
1.8
C++ Standard Library
1.9
Java
1.10
Visual Basic, Visual C++ and C#
1.11
Other High-Level Languages
1.12
Structured Programming
1.13
The Key Software Trend: Object Technology
1.14
Basics of a Typical C++ Environment
1.15
Hardware Trends
© 2003 Prentice Hall, Inc. All rights reserved.

2

Chapter 1 – Introduction to Computers
and C++ Programming
Outline
1.16
1.17
1.18
1.19
1.20
1.21
1.22
1.23
1.24
1.25
1.26

History of the Internet
History of the World Wide Web
World Wide Web Consortium (W3C)
General Notes About C++ and This Book
Introduction to C++ Programming
A Simple Program: Printing a Line of Text
Another Simple Program: Adding Two Integers
Memory Concepts
Arithmetic
Decision Making: Equality and Relational Operators
Thinking About Objects: Introduction to Object Technology
and the Unified Modeling Language


1.1 Introduction

3

• Software
– Instructions to command computer to perform actions and
make decisions

• Hardware
• Standardized version of C++
– United States
• American National Standards Institute (ANSI)

– Worldwide
• International Organization for Standardization (ISO)

• Structured programming
• Object-oriented programming

1.2

What is a Computer?

4

• Computer
– Device capable of performing computations and making
logical decisions

• Computer programs
– Sets of instructions that control computer’s processing of
data

• Hardware
– Various devices comprising computer
• Keyboard, screen, mouse, disks, memory, CD-ROM,
processing units, …

• Software
– Programs that run on computer

1.3 Computer Organization
•

5

Six logical units of computer
1. Input unit
•
•

“Receiving” section
Obtains information from input devices
– Keyboard, mouse, microphone, scanner, networks, …

1. Output unit
•
•
•

“Shipping” section
Takes information processed by computer
Places information on output devices
– Screen, printer, networks, …
– Information used to control other devices


•

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3. Memory unit
•
•
•
•

Rapid access, relatively low capacity “warehouse” section
Retains information from input unit
– Immediately available for processing
Retains processed information
– Until placed on output devices
Memory, primary memory

4. Arithmetic and logic unit (ALU)
•
•

“Manufacturing” section
Performs arithmetic calculations and logic decisions


•

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5. Central processing unit (CPU)
•
•

“Administrative” section
Supervises and coordinates other sections of computer

5. Secondary storage unit
•
•
•
•
•

Long-term, high-capacity “warehouse” section
Storage
– Inactive programs or data
Secondary storage devices
– Disks
Longer to access than primary memory
Less expensive per unit than primary memory


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1.4 Evolution of Operating Systems
• Early computers
– Single-user batch processing
• Only one job or task at a time
• Process data in groups (batches)
• Decks of punched cards

• Operating systems
– Software systems
– Manage transitions between jobs
– Increased throughput
• Amount of work computers process


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1.4 Evolution of Operating Systems
• Multiprogramming
– Many jobs or tasks sharing computer’s resources
– “Simultaneous” operation of many jobs

• Timesharing
– 1960s
– Special case of multiprogramming
– Users access computer through terminals
• Devices with keyboards and screens
• Dozens, even hundreds of users

– Perform small portion of one user’s job, then moves on to
service next user
– Advantage:
• User receives almost immediate responses to requests

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1.5 Personal Computing, Distributed
Computing, and Client/Server Computing
• Personal computers
–
–
–
–

1977: Apple Computer
Economical enough for individual
1981: IBM Personal Computer
“Standalone” units

• Computer networks
– Over telephone lines
– Local area networks (LANs)

• Distributed computing
– Organization’s computing distributed over networks


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1.5 Personal Computing, Distributed
Computing, and Client/Server Computing
• Workstations
– Provide enormous capabilities
– Information shared across networks

• Client/server computing
– File servers
• Offer common store of programs and data

– Client computers
• Access file servers across network

• UNIX, Linux, Microsoft’s Window-based systems


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1.6 Machine Languages, Assembly
Languages, and High-level Languages
•

Three types of computer languages
1. Machine language
•
•
•
•
•
•
•

Only language computer directly understands
“Natural language” of computer
Defined by hardware design
– Machine-dependent
Generally consist of strings of numbers
– Ultimately 0s and 1s
Instruct computers to perform elementary operations
– One at a time
Cumbersome for humans
Example:
+1300042774
+1400593419
+1200274027


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•

2. Assembly language
•
•
•

•

English-like abbreviations representing elementary computer
operations
Clearer to humans
Incomprehensible to computers
– Translator programs (assemblers)
• Convert to machine language
Example:
LOAD
BASEPAY
ADD
OVERPAY
STORE GROSSPAY


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•

3. High-level languages
•
•

•
•
•

Similar to everyday English, use common mathematical
notations
Single statements accomplish substantial tasks
– Assembly language requires many instructions to
accomplish simple tasks
Translator programs (compilers)
– Convert to machine language
Interpreter programs
– Directly execute high-level language programs
Example:
grossPay = basePay + overTimePay


1.7 History of C and C++
• History of C
– Evolved from two other programming languages
• BCPL and B
– “Typeless” languages

– Dennis Ritchie (Bell Laboratories)
• Added data typing, other features

– Development language of UNIX
– Hardware independent
• Portable programs

– 1989: ANSI standard
– 1990: ANSI and ISO standard published
• ANSI/ISO 9899: 1990

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1.7 History of C and C++

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• History of C++
–
–
–
–

Extension of C
Early 1980s: Bjarne Stroustrup (Bell Laboratories)
“Spruces up” C
Provides capabilities for object-oriented programming
• Objects: reusable software components
– Model items in real world
• Object-oriented programs
– Easy to understand, correct and modify

– Hybrid language
• C-like style
• Object-oriented style
• Both

1.8 C++ Standard Library

17

• C++ programs
– Built from pieces called classes and functions

• C++ standard library
– Rich collections of existing classes and functions

• “Building block approach” to creating programs
– “Software reuse”


1.9 Java
• Java
– 1991: Sun Microsystems
• Green project

– 1995: Sun Microsystems
• Formally announced Java at trade show

–
–
–
–

Web pages with dynamic and interactive content
Develop large-scale enterprise applications
Enhance functionality of web servers
Provide applications for consumer devices
• Cell phones, pagers, personal digital assistants, …


18

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1.10 Visual Basic, Visual C++ and C#
• BASIC
– Beginner’s All-Purpose Symbolic Instruction Code
– Mid-1960s: Prof. John Kemeny and Thomas Kurtz
(Dartmouth College)

• Visual Basic
– 1991
• Result of Microsoft Windows graphical user interface (GUI)
– Developed late 1980s, early 1990s

– Powerful features
• GUI, event handling, access to Win32 API, object-oriented
programming, error handling

– Visual Basic .NET

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• Visual C++
– Microsoft’s implementation of C++
• Includes extensions
• Microsoft Foundation Classes (MFC)
• Common library
– GUI, graphics, networking, multithreading, …
– Shared among Visual Basic, Visual C++, C#

• .NET platform
– Web-based applications
• Distributed to great variety of devices
– Cell phones, desktop computers

– Applications in disparate languages can communicate

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• C#
– Anders Hejlsberg and Scott Wiltamuth (Microsoft)
– Designed specifically for .NET platform
– Roots in C, C++ and Java
• Easy migration to .NET

– Event-driven, fully object-oriented, visual programming
language
– Integrated Development Environment (IDE)
• Create, run, test and debug C# programs
• Rapid Application Development (RAD)

– Language interoperability


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1.11 Other High-level Languages
• FORTRAN
– FORmula TRANslator
– 1954-1957: IBM
– Complex mathematical computations
• Scientific and engineering applications

• COBOL
– COmmon Business Oriented Language
– 1959: computer manufacturers, government and industrial
computer users
– Precise and efficient manipulation of large amounts of data
• Commercial applications


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1.11 Other High-level Languages
• Pascal
– Prof. Niklaus Wirth
– Academic use


1.12 Structured Programming

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• Structured programming (1960s)
– Disciplined approach to writing programs
– Clear, easy to test and debug, and easy to modify

• Pascal
– 1971: Niklaus Wirth

• Ada
– 1970s - early 1980s: US Department of Defense (DoD)
– Multitasking
• Programmer can specify many activities to run in parallel


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1.13 The Key Software Trend: Object
Technology
• Objects
– Reusable software components that model real world items
– Meaningful software units
• Date objects, time objects, paycheck objects, invoice objects,
audio objects, video objects, file objects, record objects, etc.
• Any noun can be represented as an object

– More understandable, better organized and easier to maintain
than procedural programming
– Favor modularity
• Software reuse
– Libraries
• MFC (Microsoft Foundation Classes)
• Rogue Wave

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1.14 Basics of a Typical C++ Environment
• C++ systems
– Program-development environment
– Language
– C++ Standard Library


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Phases of C++ Programs:
1. Edit
2. Preprocess
3. Compile

Editor

Disk

Preprocessor program
processes the code.

Compiler

Disk

Compiler creates
object code and stores
it on disk.

Linker

Disk

Preprocessor

4. Link

Loader

5. Load

Disk

6. Execute

Program is created in
the editor and stored
on disk.

Disk

Primary
Memory

Loader puts program
in memory.
.
.
.
.
.
.

Primary
Memory

CPU

.
.
.
.
.
.


Linker links the object
code with the libraries,
creates a.out and
stores it on disk

CPU takes each
instruction and
executes it, possibly
storing new data
values as the program
executes.

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• Input/output
– cin
• Standard input stream
• Normally keyboard

– cout
• Standard output stream
• Normally computer screen

– cerr
• Standard error stream
• Display error messages


1.15 Hardware Trends
• Capacities of computers
– Approximately double every year or two
– Memory used to execute programs
– Amount of secondary storage
• Disk storage
• Hold programs and data over long term

– Processor speeds
• Speed at which computers execute programs


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1.16 History of the Internet

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• Late 1960s: ARPA
– Advanced Research Projects Agency
• Department of Defense

– ARPAnet
– Electronic mail (e-mail)

• Packet switching
– Transfer digital data via small packets
– Allow multiple users to send/receive data simultaneously
over same communication paths

• No centralized control
– If one part of network fails, other parts can still operate


1.16 History of the Internet

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• TCP/IP
– Transmission Control Protocol (TCP)
• Messages routed properly
• Messages arrived intact

– Internet Protocol (IP)
• Communication among variety of networking hardware and
software
• Current architecture of Internet

• Bandwidth
– Carrying capacity of communications lines


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1.17 History of the World Wide Web
• World Wide Web
–
–
–
–

1990: Tim Berners-Lee (CERN)
Locate and view multimedia-based documents
Information instantly and conveniently accessible worldwide
Possible worldwide exposure
• Individuals and small businesses

– Changing way business done


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1.18 World Wide Web Consortium (W3C)
• World Wide Web Consortium (W3C)
–
–
–
–

1994: Tim Berners-Lee
Develop nonproprietary, interoperable technologies
Standardization organization
Three hosts
• Massachusetts Institute of Technology (MIT)
• France’s INRIA (Institut National de Recherche en
Informatique et Automatique)
• Keio University of Japan

– Over 400 members
• Primary financing
• Strategic direction


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1.18 World Wide Web Consortium (W3C)
• Recommendations
– 3 phases
• Working Draft
– Specifies evolving draft
• Candidate Recommendation
– Stable version that industry can begin to implement
• Proposed Recommendation
– Considerably mature Candidate Recommendation


1.19 General Notes About C++
and This Book

35

• Book geared toward novice programmers
– Stress programming clarity
– C and C++ are portable languages

• Portability
– C and C++ programs can run on many different computers

• Compatibility
– Many features of current versions of C++ not compatible
with older implementations


36

1.20 Introduction to C++ Programming
• C++ language
– Facilitates structured and disciplined approach to computer
program design

• Following several examples
– Illustrate many important features of C++
– Each analyzed one statement at a time

• Structured programming
• Object-oriented programming


1.21 A Simple Program:
Printing a Line of Text
• Comments
–
–
–
–

Document programs
Improve program readability
Ignored by compiler
Single-line comment
• Begin with //

• Preprocessor directives
– Processed by preprocessor before compiling
– Begin with #


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// Fig. 1.2: fig01_02.cpp
// A first program in C++.
Function main
#include <iostream>

Single-line comments.

Outline

returns an
integer value. begins Preprocessor directive to
Left brace {
function
include input/output Statements end with afig01_02.cpp
stream
begins program execution appears
body.
Function main
(1 of 1)
header file <iostream>.
exactly once in every C++ semicolon ;.
program..
fig01_02.cpp

// function main
int main()
{
std::cout << "Welcome to C++!n";
return 0;

//

} // end function

Welcome to C++!

Corresponding right brace }
indicate that program ended successfully
ends function body.
Stream insertion
Name cout belongs to operator.
main namespace std.
Keyword return is one of
several means to exit
function; value 0 indicates
program terminated
successfully.

output (1 of 1)

© 2003 Prentice Hall, Inc.
All rights reserved.

38


39

• Standard output stream object
– std::cout
– “Connected” to screen
– <<
• Stream insertion operator
• Value to right (right operand) inserted into output stream

• Namespace
– std:: specifies using name that belongs to “namespace”
std
– std:: removed through use of using statements

• Escape characters
–
– Indicates “special” character output


40

Escape Sequence

Description

n

Newline. Position the screen cursor to the
beginning of the next line.

t

Horizontal tab. Move the screen cursor to the next
tab stop.

r

Carriage return. Position the screen cursor to the
beginning of the current line; do not advance to the
next line.

a

Alert. Sound the system bell.

Backslash. Used to print a backslash character.

"

Double quote. Used to print a double quote
character.


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Outline

// Fig. 1.4: fig01_04.cpp
// Printing a line with multiple statements.
#include <iostream>
// function main begins program execution
int main()
{
std::cout << "Welcome ";
std::cout << "to C++!n";
return 0;

fig01_04.cpp
Multiple stream insertion
(1 of 1)
statements produce one line of
output.
fig01_04.cpp
output (1 of 1)

// indicate that program ended successfully

} // end function main

Welcome to C++!


41

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2
3
4
5
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7
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10
11
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Outline

// Fig. 1.5: fig01_05.cpp
// Printing multiple lines with a single statement
#include <iostream>
// function main begins program execution Using newline characters
print on multiple lines.
int main()
{
std::cout << "WelcomentonnC++!n";
return 0;

to

fig01_05.cpp
(1 of 1)
fig01_05.cpp
output (1 of 1)



Welcome
to
C++!


42

1.22 Another Simple Program:
Adding Two Integers

43

• Variables
– Location in memory where value can be stored
– Common data types
• int - integer numbers
• char - characters
• double - floating point numbers

– Declare variables with name and data type before use
int integer1;
int integer2;
int sum;

– Can declare several variables of same type in one declaration
• Comma-separated list
int integer1, integer2, sum;

Adding Two Integers
• Variables
– Variable names
• Valid identifier
– Series of characters (letters, digits, underscores)
– Cannot begin with digit
– Case sensitive


44

Adding Two Integers

45

• Input stream object
– >> (stream extraction operator)
• Used with std::cin
• Waits for user to input value, then press Enter (Return) key
• Stores value in variable to right of operator
– Converts value to variable data type

• = (assignment operator)
– Assigns value to variable
– Binary operator (two operands)
– Example:
sum = variable1 + variable2;


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Outline

// Fig. 1.6: fig01_06.cpp
// Addition program.
#include <iostream>
int main()
Declare integer variables.
{
int integer1; // first number to be input by user
int integer2; // second number to be input by user
Use stream extraction
int sum;
// variable in which sum will be stored
std::cout << "Enter first
std::cin >> integer1;

fig01_06.cpp
(1 of 1)

operator with standard input
stream to obtain user input.
integern"; // prompt

// read an integer

std::cout << "Enter second integern"; // prompt
Calculations // read an integer output
can be performed in

statements:
Stream manipulatoralternative for
lines 18 and 20:
std::endl outputs a
sum = integer1 + integer2; // assign result to sum
newline, then “flushes output
std::cout << "Sum is " << integer1 + integer2 << std::endl;
std::cout << "Sum is " << sum << std::endl; // print sum buffer.”
return 0;



Concatenating, chaining or
cascading stream insertion
operations.

46

Enter first integer
45
Enter second integer
72
Sum is 117

Outline
fig01_06.cpp
output (1 of 1)


47

1.23 Memory Concepts

48

• Variable names
– Correspond to actual locations in computer's memory
– Every variable has name, type, size and value
– When new value placed into variable, overwrites previous
value
– Reading variables from memory nondestructive


49

1.23 Memory Concepts

integer1

45


integer1

45

– Assume user entered 72

integer2

72

integer1

45

integer2

72

– Assume user entered 45

sum = integer1 + integer2;

sum


117

1.24

Arithmetic

• Arithmetic calculations
– *
• Multiplication

– /
• Division
• Integer division truncates remainder
– 7 / 5 evaluates to 1

– %
• Modulus operator returns remainder
– 7 % 5 evaluates to 2


50

1.24

Arithmetic

51

• Rules of operator precedence
– Operators in parentheses evaluated first
• Nested/embedded parentheses
– Operators in innermost pair first

– Multiplication, division, modulus applied next
• Operators applied from left to right

– Addition, subtraction applied last
Operator(s)

Operation(s)
Order to right
• Operators applied from leftof evaluation (precedence)

()

Parentheses

*, /, or %

Multiplication Division Evaluated second. If there are several, they re
Modulus
evaluated left to right.

+ or -

Addition
Subtraction


Evaluated first. If the parentheses are nested, the
expression in the innermost pair is evaluated first. If
there are several pairs of parentheses “on the same level”
(i.e., not nested), they are evaluated left to right.

Evaluated last. If there are several, they are
evaluated left to right.

52

1.25 Decision Making: Equality and
Relational Operators
• if structure
– Make decision based on truth or falsity of condition
• If condition met, body executed
• Else, body not executed

• Equality and relational operators
– Equality operators
• Same level of precedence

– Relational operators
• Same level of precedence

– Associate left to right


53

Standard algebraic
equality operator or
relational operator

C++ equality
or relational
operator

Example
of C++
condition

Meaning of
C++ condition

>

>

x > y

x is greater than y

<

<

x < y

x is less than y

≥

>=

x >= y

x is greater than or equal to y

≤

<=

x <= y

x is less than or equal to y

=

==

x == y

x is equal to y

≠

!=

x != y

x is not equal to y

Relational operators

Equality operators


54

• using statements
– Eliminate use of std:: prefix
– Write cout instead of std::cout


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Outline

// Fig. 1.14: fig01_14.cpp
// Using if statements, relational
// operators, and equality operators.
#include <iostream>
using std::cout;
using std::cin;
using std::endl;

// program uses cout
// program uses cin
// program uses endl

fig01_14.cpp
(1 of 2)
using statements eliminate
need for std:: prefix.

Declare variables.
int main()
{
Can to be read from user
int num1; // first number write cout and cin
without std:: prefix.
int num2; // second number to be read from user
cout << "Enter two integers, and I will tell youn"
if structure compares values
<< "the relationships they satisfy: ";
of num1 and num2 to test for
If
cin >> num1 >> num2;
// read two integerscondition is true
if ( num1 == num2 )
cout << num1 << " is

(i.e.,
equality.
values are equal), execute this
if structure compares values
statement.
If << endl;
of to " and num2 to test is
equal num1<< num2 condition fortrue (i.e.,
values are not equal), execute
inequality.
this statement.

if ( num1 != num2 )
cout << num1 << " is not equal to " << num2 << endl;


55

26
27
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if ( num1 < num2 )
cout << num1 << " is less than " << num2 << endl;
if ( num1 > num2 )
cout << num1 << " is greater than " << num2 << endl;
if ( num1 <= num2 )
cout << num1 << " is less than or equal to "
<< num2 << endl;

Outline
fig01_14.cpp
Statements of 2) be split over
(2 may
several lines.
fig01_14.cpp
output (1 of 2)

if ( num1 >= num2 )
cout << num1 << " is greater than or equal to "
<< num2 << endl;
return 0;



Enter two integers, and I will tell you
the relationships they satisfy: 22 12
22 is not equal to 12
22 is greater than 12
22 is greater than or equal to 12


56

Enter two integers, and I will tell you
the relationships they satisfy: 7 7
7 is equal to 7
7 is less than or equal to 7
7 is greater than or equal to 7

Outline
fig01_14.cpp
output (2 of 2)


57

58
1.26 Thinking About Objects: Introduction to
Object Technology and the Unified
Modeling Language

• Object oriented programming (OOP)
– Model real-world objects with software counterparts
– Attributes (state) - properties of objects
• Size, shape, color, weight, etc.

– Behaviors (operations) - actions
• A ball rolls, bounces, inflates and deflates
• Objects can perform actions as well

– Inheritance
• New classes of objects absorb characteristics from existing classes

– Objects
• Encapsulate data and functions
• Information hiding
– Communicate across well-defined interfaces

59
Modeling Language
• User-defined types (classes, components)
– Data members
• Data components of class

– Member functions
• Function components of class

– Association
– Reuse classes


60
Modeling Language
• Object-oriented analysis and design (OOAD)
process
– Analysis of project’s requirements
– Design for satisfying requirements
– Pseudocode
• Informal means of expressing program
• Outline to guide code


61
Modeling Language
• Unified Modeling Language (UML)
– 2001: Object Management Group (OMG)
• Released UML version 1.4

– Model object-oriented systems and aid design
– Flexible
• Extendable
• Independent of many OOAD processes
• One standard set of notations

– Complex, feature-rich graphical language


1. intro to comp & c++ programming

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